Ill effects of vacuum canister removal and other vacuum/map questions?

[gcurtis]

Agreed.

Here is some factual information from the FSM.

Page 8H-1 under Cruise Control:

"The speed control system is electronically controlled and vacuum operated..."

They go on to discuss the vacuum canister and checking it for leaks under troubleshooting.

... And page 24-11 under HVAC:

"Engine vacuum is stored in the vacuum reservior. The stored vacuum is used to operate the vacuum-controlled vehicle accessories during periods of low engine vacuum such as when the vehicle is climbing a steep grade, or under high engine load operating conditions."

***these are quotes from the 1999 Jeep Cherokee Factory Service Manual, copywrite 1998 by Chrysler Corporation, not speculation, heresay or other BS.

 

[johnnyc]

i am getting bad gas milage and think this may be causing it.

You mentioned bad gas mileage in your first post. Try, just try to hook the canister back up and see if there's any difference in mileage and drivability. Then you can do whatever you feel is best.

 

[redyouch]

Agreed.

Here is some factual information from the FSM.

Page 8H-1 under Cruise Control:

"The speed control system is electronically controlled and vacuum operated..."

They go on to discuss the vacuum canister and checking it for leaks under troubleshooting.

... And page 24-11 under HVAC:

"Engine vacuum is stored in the vacuum reservior. The stored vacuum is used to operate the vacuum-controlled vehicle accessories during periods of low engine vacuum such as when the vehicle is climbing a steep grade, or under high engine load operating conditions."

***these are quotes from the 1999 Jeep Cherokee Factory Service Manual, copywrite 1998 by Chrysler Corporation, not speculation, heresay or other BS.

ok so at high RPM/high load conditions the vacuum will suffer. could this could affect map/ fuel pressure reg? they are connect directly to the intake. so i guess i should put it back in. there isnt alot of good places on the pass side to put it, does it need to be at the end of the line of vacuum hose after the cruise control?

thanks for your helpful response it is highly appreciated.

 

[gcurtis]

You're welcome.

As for where to put it, I've got an engine compartment crammed with stuff (OBA, controllers, FIPK etc). I was able to put it back up under the bumper with some strapping material and a sheet metal screw or two (couple of bucks at the hardware store). I've also seen it up near the firewall under some of the AC lines.

Check both spots out, you'll find a spot.

 

[redyouch]

You're welcome.

As for where to put it, I've got an engine compartment crammed with stuff (OBA, controllers, FIPK etc). I was able to put it back up under the bumper with some strapping material and a sheet metal screw or two (couple of bucks at the hardware store). I've also seen it up near the firewall under some of the AC lines.

Check both spots out, you'll find a spot.

alright thanks alot for all your help.

 

[sidriptide]

low-vacuum occurs when the throttle is opened up. climbing a hill and pressing the throttle is a perfect example. just because the engine is spinning faster doesnt ALWAYS mean increased vacuum.

 

[Jeepsterboy101]

there isnt alot of good places on the pass side to put it, does it need to be at the end of the line of vacuum hose after the cruise control?

I am wondering the same thing......wasn't able to put mine back after my bumper install. So I was just wondering the same thing.

 

[gcurtis]

I am wondering the same thing......wasn't able to put mine back after my bumper install. So I was just wondering the same thing.

Look up by the evap. cannister, near the firewall and down low, near the fenderwell.

 

[mack]

hmmm....i better find mine, i just don't understand why i didn't see any probs when i removed it, i was always told it was for just the CC.
anyone have one kickin around??...:laugh3:

 

[Starscream]

Did Vacuum once offend you or date your sister?

Actually it did, and I can't wait to see his happy ass again. *cocks 9mm*

 

[gcurtis]

Actually it did, and I can't wait to see his happy ass again. *cocks 9mm*

Now there is someone who gets humor.

 

[lrsmithwhaley]

i crushed mine during a wheeling trip a couple months back. the only time it would cause major issues is if you have a vacuum disconnect front axle. you would loose that function. otherwise it theoretically should mess up the cruise control and possibly the heater controls. but i believe that may have been on some of the older models. other than the disconnect axle if you loose anything it will only be creature comforts. nothing emissions or driving related.

Bringing back from the dead. I have a vacuum disconnect axle and I accidently broke my line to the tube and have the end taped up until I stop being lazy and relocate the tube. Even before I taped the line I never lost 4wd. How do I know? Because I was using 4wd later that day and for the next few days in the snow.

 

[rocklandxjer]

this thread was about the vacuum canister behind the bumper, i dont think that has much to do with the vacuum disco of the axle. i thought there was some sort of actuator in that little box on the axle, maybe not... now im not sure...

 

[BlueCuda]

Ditched mine when I changed bumpers. Everything works 100% and has been for going on 2 years now.

Kind of OT but a friend of mine had a 97 Country that didn't have one, but my 97 Did. His was 100% stock when he got it.

 

[Starscream]

Kind of OT but a friend of mine had a 97 Country that didn't have one, but my 97 Did. His was 100% stock when he got it.

I highly doubt that, but since I'm not 100% sure I won't call SPOBI just yet.

 

[BlueCuda]

I highly doubt that, but since I'm not 100% sure I won't call SPOBI just yet.

Could have been wrecked or something and a body shop or someone removed it? But he seriously didn't have one.

 

[Starscream]

Could have been wrecked or something and a body shop or someone removed it? But he seriously didn't have one.

I'm not doubting he didn't have one, but saying it's 100% OEM without one I don't believe.

 

[mack]

i took mine off when i did my bumper, "I" never seen a change in anything, heater controls or anything, but after this very same thread came up, i said "what the heck" went to the junkyard and got one for $5.....everything still work's the same...:dunno:

 

[JEONLYEP]

I've got a disco axle and haven't had the canister in the front for two years now. Everything that's left on my Jeep that needs vacuum to work still works (no ac anymore, but that's a different story). As a matter of fact the reason I unhooked the canister in the first place was to find out where the vacuum leak was that caused my heater to blow through the defroster all the time. I was told that the vac lines around the battery are the first place to look. Just before the vac lines get to the battery there was a tee in the line. I capped the one going on up to the canister and everything has worked since. I always intended on replacing that line until one day I broke the canister, so I said forget it.

DAryl